The present invention relates to the manufacture of disposable contraceptive intravaginal barriers. It also relates to the methods for making these disposable barriers.
Recent incidence of complications with the intrauterine device (IUD) and the contraceptive pill has led women throughout the world to revert to reusable cervical contraceptive pessaries such as the diaphragm and other related cervical pessaries such as the cervical cap, the vault cap, and the vimule. These pessaries, although not as effective as the IUD and the pill preventing pregnancy, have shown no adverse physiological or systemic effects.
Currently available cervical pessaries such as the diaphragm and related cervical pessaries are generally made in the form of a soft rubber cap with a metal spring embedded in the rim. These pessaries present certain disadvantages that operate to discourage their widespread use. Some of these disadvantages are as follows: their effectiveness is substantially lower than the pill, the IUD, and injectable hormones; prior to insertion they must be coated with spermicidal foam or jelly; after use they must be cleaned and properly stored (this requirement discourages their use especially in areas of the world where water is not readily available); and, because of the cost of spermicides, cervical pessaries can become expensive if used frequently.
The present invention provides a method of manufacturing a disposable cervical barrier that eliminates the disadvantages of currently available cervical pessaries. It provides a method of manufacturing a disposable cervical barrier made chiefly of plastic foam, preferably polyurethane foam, that is preimpregnated with medicament, such as spermicide, germicide, or an abortion inducing agent, that is activated by contact with a small amount of water or any aqueous solution, including internal secretions. Thus, preparation is made easier and preparation time shorter, factors that encourage the use of the present device. In addition, this disposable pessary approaches the effectiveness of the pill.
The medicament can also be "time encapsulated" so that it is activated for a preset time period upon contact with an aqueous solution.
The present invention also relates to two methods for making these disposable barriers.
A conventional assembly procedure to produce a finished pessary from open cell bulk form would have to follow a number of labor intensive and time consuming steps in the following general sequence: One: cutting two parallel blocks of foam; two: machining the blocks into two mating half hollow spheres; three: coating the mating sides of said half spheres with some impermeable viscous medium such as latex; four: assembling the two matching parts for adhesion and curing; five: cleaning and neutralizing the foam assembly; six: dip saturation of the polyurethane foam elements with a suitable concentration of spermicides; and seven: sterilization of the finished article and packaging.
Two efficient and labor saving methods of making disposable pessaries are described here. One method is a "wet foam," or "quick foam," technology that utilizes a method of adding the medicament to liquid plastic foam, preferably polyurethane foam. This would require only one, two, or three steps, depending on the number of protective layers required in the cervical barrier.